Sorry, Not my picture. I found it on the Internet.

Also there's another vacuum line on the other side of the engine. What does that do vs the one we're talking about?

 

On the Durango, I don't know. Even the heater core location took me by surprise. I am used to them being on the other side of the truck.

 

LOL. good to know.

I have a feeling that the defrost issue and the cruise are related. I need to find a vacuum diagram and see if they share any hoses.

The cruise turns on so it's not an electrical issue.

 

It is highly likely that the issues are related. Find the vacuum leak, fix it, and I bet both systems start working the way they are supposed to.

 

Throwing my $0.02 in on this one.....when I had to replace the fan motor and resistor on my 2000 Durango (4x with the 4.7 but should be pretty spot on for vacuum lines) there was a "reservoir" for the vacuum under the cowling below the wiper arms on the passenger side. If memory serves me correctly that is the vacuum for the cruise.....the one on the drivers side below the heater core should serve the controls for the heater. You can take the dash face off and pull the gauge cluster and most likely the radio for room (and maybe the lower kick panel below the steering column) to get at the vacuum lines for the heater controls. I will see if I can link my post to this reply and put some pics up if I still have them....

*** Edit *** my actual pictures are not much help nor is my earlier post that I put up about changing out my fan motor and the blower resistor, but I DID find the vacuum diagram that I used when trouble shooting the issue:

Simplified vacuum hose diagram. Note the multi colored 7 hose connector as depicted in the upper right side of the picture runs from the HVAC controls to the system under the dash

Hope this helps.

Steve